The cause of Benjamin Seitz's death was hyperthermia because of environmental exposure, the state medical examiner said on Wednesday.

On July 7, Kyle Seitz was supposed to drop his son off at day care in Ridgefield, Connecticut, but the drop-off never occurred, his wife, Lindsey Rogers-Seitz told CNN last month.

Seitz drove to work, and at the end of the day he went to pick Ben up at day care, only to realize he was not there.

That was when Seitz found his son in the car. He rushed the child to the hospital, but Ben had died.

No criminal charges have been announced in the boy's death, but state prosecutors said Wednesday that the criminal investigation is "ongoing."

"The autopsy report is one factor to be considered by the state's attorney in the evaluation of the incident once the investigation is complete," a statement released by State's Attorney Stephen J. Sedensky said.

Neither prosecutors nor Ridgefield Police provided further comment.

Despite the medical examiner's ruling, the decision about whether to press criminal charges is made by the state's attorney, said CNN Legal Analyst Paul Callan.

"The use of the word 'homicide' in an autopsy report, though often seen in connection with criminal cases, does not necessarily mean that criminal charges will be lodged against the father," Callan said.

"In legal parlance, the term means that death was caused by another human being rather than by strictly natural causes," he added.

Benjamin Seitz's death came in the wake of the June case of 22-month-old Cooper Harris, whose death after being left in a hot car in Georgia drew international attention.

His father, Justin Ross Harris, pleaded not guilty to murder and child cruelty charges after leaving Cooper in the backseat of his car for an entire workday in the sweltering heat.

Harris said he forgot the child was in the car. Investigators say he researched how hot a car needs to be to kill a child, and that while his son was dying in the parking lot, Harris was sending explicit text messages to several women.

According to child advocacy group KidsAndCars.org, 44 children died of heatstroke in cars in 2013, and more than 500 have died in hot cars since 2000.

In the wake of his death, Rogers-Seitz created a blog called "The Gift of Ben," which she has said she is using to bring attention to the number of children who die of heatstroke in cars and to press for action to save lives.

About 50% of cases involving deaths of infants abandoned in automobiles result in criminal charges, Callan said, adding that each case is "highly individual."

"The criminal law generally does not punish for accidental events absent evidence of gross negligence, recklessness or a depraved indifference to the value of human life," Callan said.

Seitz family attorney Bob Gulash told CNN he could not comment on the ongoing investigation.

In a post from August 15, Rogers-Seitz wrote that she "realized the hardest part of this journey is not that we believe we cannot live without you, Ben. It is that we know and feel we have a long life ahead of us, and we must live it without you physically in our arms."